Position detector and exposure apparatus

Abstract

A position detector includes a first planar encoder including a first encoder head unit mounted on a test object that is a movable member, and a first grating unit mounted on a fixed member, the first planar encoder being configured to detect a position of the test object in two directions by measuring a position of the first grating unit using the first encoder head unit, and a second planar encoder including a second encoder head unit mounted on the fixed member, and a second grating unit mounted on the movable member, the second planar encoder being used to generate data for calibrating the position of the first grating unit measured by the first encoder head unit.

1. A position detector comprising:
 a first planar encoder including a first encoder head unit mounted on a test object that is a movable member, and a first grating unit mounted on a fixed member, the first planar encoder being configured to detect a position of the test object in two directions by measuring a position of the first grating unit using the first encoder head unit; and 
 a second planar encoder including a second encoder head unit mounted on the fixed member, and a second grating unit mounted on the movable member, the second planar encoder being used to generate data for calibrating the position of the first grating unit measured by the first encoder head unit. 
 
     
     
       2. The position detector according to  claim 1 , wherein the second planar encoder generates the data as a result of that the first encoder head unit measures the first grating unit by driving the test object in one of the two directions while a height and an inclination of the second grating unit are maintained in a direction orthogonal to the two directions. 
     
     
       3. The position detector according to  claim 1 , wherein the second grating unit includes a pair of scale members corresponding to the two directions, and an origin scale,
 wherein the second encoder head unit includes a pair of encoder heads configured to detect the pair of scale members, and an origin detection head configured to detect the origin scale, and 
 wherein the pair of encoder heads and the origin detection head detect an origin. 
 
     
     
       4. The position detector according to  claim 1 , wherein the two directions are orthogonal to each other, and the first grating unit has a pattern that extends in a +45° or −45° direction relative to both of the two directions. 
     
     
       5. The position detector according to  claim 1 , further comprising a top plate configured to house the first encoder head unit and the second grating unit in the test object. 
     
     
       6. The position detector according to  claim 1 , wherein in one of the two directions, a grating of the second grating unit is integrated with a grating of the first encoder head unit. 
     
     
       7. An exposure apparatus comprising a position detector that includes:
 a first planar encoder including a first encoder head unit mounted on a test object that is a movable member, and a first grating unit mounted on a fixed member, the first planar encoder being configured to detect a position of the test object in two directions by measuring a position of the first grating unit using the first encoder head unit; and 
 a second planar encoder including a second encoder head unit mounted on the fixed member, and a second grating unit mounted on the movable member, the second planar encoder being used to generate data for calibrating the position of the first grating unit measured by the first encoder head unit. 
 
     
     
       8. The exposure apparatus according to  claim 7 , wherein the position detector includes a first position detector and a second position detector,
 wherein the exposure apparatus further comprises: 
 an exposure unit that includes a first substrate stage configured to support and drive a substrate, the first position detector configured to detect a position of the first substrate stage, and a projection optical system configured to project a pattern of an original onto the substrate, the exposure unit being configured to expose the substrate via a liquid that is filled in a space between the projection optical system and the substrate; and 
 a measurement unit configured to obtain alignment information and focus information of the substrate, the measurement unit including a second substrate stage configured to support and drive the substrate, and the second position detector configured to detect a position of the second substrate stage, and 
 wherein the second grating unit of the first position detector and the second grating unit of the second position detector are arranged outside of a channel in which the substrate measured by the measurement unit is moved from the second substrate stage to the first substrate stage. 
 
     
     
       9. The exposure apparatus according to  claim 7 , further comprising a substrate stage configured to support and drive a substrate,
 wherein the position detector detects a position of the substrate stage, and 
 wherein the second encoder head unit includes an encoder head arranged at a position such that the encoder head can measure the second grating unit when the substrate stage is arranged at a position used to observe a reference mark of the substrate stage via a projection optical system. 
 
     
     
       10. A device manufacturing method comprising the steps of:
 exposing a substrate using an exposure apparatus including a position detector; and 
 developing the substrate that has been exposed, 
 wherein the position detector includes: 
 a first planar encoder including a first encoder head unit mounted on a test object that is a movable member, and a first grating unit mounted on a fixed member, the first planar encoder being configured to detect a position of the test object in two directions by measuring a position of the first grating unit using the first encoder head unit; and 
 a second planar encoder including a second encoder head unit mounted on the fixed member, and a second grating unit mounted on the movable member, the second planar encoder being used to generate data for calibrating the position of the first grating unit measured by the first encoder head unit.